This project is designed to characterize cytogenetic and metabolic differences between normal and malignant tissues. This goal is being approached both in an animal tumor system and in a human malignancy. The animal system utilizes the H4-II-E rat hepatoma cell line established by Potter from the Reuber H-35 hepatoma. The human malignancy under study is chronic granulocytic leukemia. Both of these "transformed" systems have chromosomal abnormalities. The proposed studies are designed to determine possible relationships between chromosome abnormalities and biochemical characteristics of malignant tissues and possible mechanisms for the observed phenotypic variations. The DNA repair studies are preliminary to possible studies relating repair to transformation and chromosomal rearrangement.